An overview of pharmacology, including the history of pharmacology, drug classifications, routes of drug administration, and the role of pharmacology in nursing practice.
Introduction to Pharmacology – Study Notes
| Aspect | Definition |
|---|---|
| Scope | The scientific study of drugs and their interactions with living organisms. |
| Goal | Understand how drugs produce therapeutic effects, how they are processed by the body, and how to use them safely and effectively. |
| Branches | • Pharmacodynamics – what the drug does to the body. • Pharmacokinetics – what the body does to the drug. • Clinical Pharmacology – application in patient care. • Toxicology – harmful effects and overdose management. • Pharmacogenomics – genetic influences on drug response. |
| Term | Meaning |
|---|---|
| Drug | Any chemical substance that alters normal physiological functions when administered. |
| Medication | A drug prepared for therapeutic use (dose form, packaging, labeling). |
| Dose | Amount of drug given at one time. |
| Regimen | Schedule of doses (frequency, duration). |
| Therapeutic Index (TI) | Ratio of toxic dose to effective dose; a measure of safety. |
| Adverse Effect | Unintended, harmful response to a drug at normal doses. |
| Contra‑indication | Situation where a drug should not be used because risks outweigh benefits. |
| Interaction | Modification of a drug’s effect by another drug, food, or disease. |
| Concept | Description |
|---|---|
| Receptor | Protein (or other molecule) that a drug binds to, initiating a biological response. |
| Agonist | Binds to a receptor and activates it (e.g., morphine → μ‑opioid receptor). |
| Antagonist | Binds without activating, blocking the receptor (e.g., naloxone). |
| Partial Agonist | Produces a sub‑maximal response even at full receptor occupancy (e.g., buprenorphine). |
| Dose‑Response Curve | Graph of effect magnitude vs. drug concentration; key parameters: ED₅₀, EC₅₀, Emax. |
| Potency | Amount of drug needed to achieve a given effect (lower dose = higher potency). |
| Efficacy | Ability of a drug to produce a maximal response when all receptors are occupied. |
| Phase | Definition | Key Processes | Typical Units |
|---|---|---|---|
| Absorption | Entry of drug from site of administration into systemic circulation. | Diffusion, active transport, first‑pass metabolism (oral). | % dose absorbed, Cmax, Tmax |
| Distribution | Movement of drug from blood to tissues. | Protein binding, tissue binding, volume of distribution (Vd). | L/kg |
| Metabolism | Chemical alteration (usually in liver). | Phase I (oxidation, reduction, hydrolysis) & Phase II (conjugation). | Clearance (Cl), half‑life (t½) |
| Excretion | Removal of drug or metabolites from the body. | Renal filtration/secretion, biliary excretion, pulmonary elimination. | mL/min, % unchanged drug in urine |
Key Equations